Observation of In Growth Modes on Si(111)-√3×√3-Ga Using an Ultrahigh-Vacuum Scanning Electron Microscope

Abstract

Epitaxial growth of In layer on Si(111)-√3×√3-Ga was observed using an ultrahigh-vacuum scanning electron microscope (UHV-SEM). √3×√3-Ga (1/3 ML) and √3×√3-Ga [(1/3+2/3) ML] surfaces were prepared. The latter was formed by deposition of 2/3 ML of Ga on the √3×√3-Ga (1/3 ML) surface at room temperature. After 2 ML of In were deposited on the √3×√3-Ga (1/3 ML) surface, √7×√7 and √3×√3 structures appeared. These structures were clearly observed in the SEM images. Around the steps, ditches were observed. At the In thickness of 6 ML, flat islands with various thicknesses were observed. When 2 ML of In were deposited on the √3×√3-Ga [(1/3+2/3) ML] surface, √3/2×√3/2 structure appeared. All the terraces showed the same number of atomic layers without steps. For further In deposition the terraces had various thicknesses which differed stepwise by one atomic layer.